Process of producing anthraquinone



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To all whom it may concern:

Be it known that I, GEORGE C. BAILEY, a

' 6 son and State of New Jersey, have invented certain new and useful Improvements in Processes of Producing Anthaquinone, of which the following is a specification.

This ifiventionrelates to improvements in 1 the usual method of producinganthraquinone from benzoyl-benzoic acid and also the derivatives of anthraquinone from the corresnding' derivatives of benzoyl-benzoic aci.

sSince the supply of anthracene available in coal tar is limited and the demand for anthraquinonelis considerable, the production of anthra uinone from other sources than by the oxi ation of anthracene is very desirable. Similarly 2-methyl-anthraqu'inone necessary for certain vat dyes is required to be made synthetically, as there is little methyl-anthraoene available in coal tar. It is possible to synthesize anthraquinone from phthalic acid anhydride and benzene'by a modification of the Friedel and Crafts reaction using anhydrous aluminum chloride. In this reaction there is formed first benzoylbenzoic acid which is condensed by the use- 3 oi sulfuric acid into anthraquinone. In a similar way derivatives of benzoyl-benzoic acid may be made. For example, from toluene and phthalic acid anhydride tolylbenzoic'acid is formed; from hthalic acid anhydride and chlorobenzene c lorobenzoylbenzoic acid, and from these derivatives of benzoyl-benzoic acid the corresponding derivatives of anthraquinone are ormed. The condensation of the phthalic acid anhydride 40 and the hydrocarbon is a fairly simple process, but unless special precautions are taken the condensation of the benzoyl-benzoic acid or derivatives to obtain anthraquinone or derivatives is very troublesome.

For example, 1n the preparation of 2- methyl-anthraquinone, phthalic acid anhydride and toluene are condensed with aluininum' chloride and the tolyl-benzoic acid chtained. This dried acid is then heated with strong sulfuric acid or oleum at elevated temperatures for several hours in order to form the Q-methyl-anthraquinone. In order to obtain the methgl-anthraquinone it is necessary to dilute t e sulfuric acid to prerersr see n is. m, esisionoa so one race or HEW sens.

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cipitate the compound, for it is SOlulJlB in the strong. sulfuric acid and very insoluble in the weak sulfuric acid. However, if this dilutionisnot carried out properly the 2- methyl-anthraquinone se arates 1n such formthat filtration is a 0st impossible.

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Such a result will happen if the, acid mixture is allowedto cool and is. then poured into cold water.-

One of the objects of this'invention is to overcome-the dificultv above referred to. I have found that if the mixture containing the hot sulfuric acid be poured into hot water as rapidly as convenient, without allowing the mass to boil over, and the mixture be agitated for a few minutes, the methyl-anthraquinone will so arate in such well defined form that it is readily filtered. The aentatmn of the mixture may be accomp ished by blowing steam into the tank which contains the water. The dilution water may be heated in-this way if desired, and the blowing of steam continued during the introduction of the hot sulfuric. acid solution, although this is not necessa to secure the methyl-anthraquinone in wel defined crystals, as other methods for-agitation and for heating the water may be used.

The same process may be applied to the pre ara-tion of anthra uinone or beta-chlorant raquinone and ot or derivatives from the corresponding benzoybbenzoicacid or its derivatives. H a

That is, other compounds of the anthrauinone type, such as anthra uinone. or its erivatives, may be reduce in the same way as above describe for the production of methyl-anthraquinone by treating the corresponding benzoyl-benzoic acid; In the specification and claims the termsanthraquinone and benzoyl-benzoic acid are to be understood in this broad or eneric sense to include the substances and t eir derivatives or substitution products.

I claim:

1. That step in the production of a compound of the anthraquinonc ty t which comrises treating the corresponng benzoylnzoic acid with strong sulfuric acid at an elevated temperature and introducing the products into hot water.

2. That step in the production of a compound of the anthraqulnone type which comprises treating the corresponding benzoylcomprises fireating zthe cormspam zoyl-benzoic acid with stmng'sulfmnc mid benzuic midi with sfammg sulfuric midi m an elevated fi kem emibum smdi .immfiucimg we products Whi Em mm but wpflbuaxn 3. Thatstepim the production @f a campowmdi of the ammhnmquinum $375 15 which mg bermm: an elevated item Mature and introducing the products into 0t Waiter an& agitating 4, That step in the proclamation of a compmmdl of tha sm nhmquinomca flay a whgich cam priss \hremhimg the correspon img [cenzamfl- Tommie acid with fimmg sufifxmric mid} at @ll'awmfcadtempemwm and. imtmdmimg the poumlof ithaa mfshmquimme flay-pa which wwriss 'fmmimg the mmaespmding Pomzwyl enmic mid-with strong sulfuric mini at an slam-zed tampemwm and dillufiimg with but Wat/aw;

Em wstimomy Wheremf )I ssfifixmmy sigmfiumg GEQRGE G, BAILEY. 

